The present invention relates to a modular hearing aid for arrangement in a user's ear, particularly completely inside the ear canal, comprising a hollow plug adapted to the ear canal and having a generally irregular conical shape and an outward opening which is covered by a faceplate in which a recess is formed for removable arrangement of a battery as well as an electronic module comprising a microphone, a signal processing part and a sound reproducer.
While conventional hearing aids in a so-called BTE design for arrangement behind a user's ear are usually manufactured with a housing of a size that allows relatively easy separation for replacement of battery and possibly removal of electronic components for repair, etc., hearing aids of the above designs, i.e., of a so-called ITE design for arrangement in the ear, normally in the funnel-shaped outer part of the ear canal, or of a so-called CIC design for arrangement completely inside the ear canal, require a very compact design of the housing or plug of the hearing aid to allow it partly to be arranged in the ear canal, partly to house the components necessary for operation of the hearing aid, such as battery and electronic components for sound reception, signal processing and sound reproduction.
For manufacturing reasons, such hearing aids are therefore normally built up by joining together a plug or shell, which is adapted in shape and dimensions to the ear canal of the actual user and has an external faceplate to which the electronic components are glued or otherwise fastened so that by gluing of the faceplate to the user-adapted plug or shell they are localized therein in a protected manner. In conventional hearing aids of this type, such as are known from, e.g., EP A2-0 311 233 and U.S. Pat. No. 4,680,799, it is therefore usually necessary in connection with replacement or repair of electronic components to break the shell or the faceplate by milling or in any other way, which renders repairs difficult and more expensive and means that the shell and/or the faceplate must be re-established after repair.
An attempt has been made to alleviate the disadvantages connected with this by means of a hearing aid design known from DE-C1-41 21 311, in which the microphone part and the signal processing part of an electronic module are placed together with the battery in an insert part for removable mounting in the faceplate.
This insert part or mounting plate is, however, relatively large compared with the overall size of the faceplate and therefore requires a corresponding increase of the size of the recess, which limits the possibilities of final adaptation of the external contour of the faceplate, for example by buffing in connection with joining the faceplate with the user-adapted shell or plug, to an undesired degree. Further-more, the manufacturing of these known hearing aids is made more complicated and expensive by the requirement for a separate insert part or mounting plate for the electronic components.
In another design known from U.S. Pat. No. 5,201,008, an electronic module is removably fastened in a faceplate, here constituted by a rim portion at the external orifice of the user-adapted plug or shell, which is closed in its entirety by a hinge-connected lid. This apparatus design is substantially more complex and expensive due to the need for a separate holder for the electronic module and a complicated lid design.